DEDD regulates degradation of intermediate filaments during apoptosis

J Cell Biol. 2002 Sep 16;158(6):1051-66. doi: 10.1083/jcb.200112124. Epub 2002 Sep 16.

Abstract

Apoptosis depends critically on regulated cytoskeletal reorganization events in a cell. We demonstrate that death effector domain containing DNA binding protein (DEDD), a highly conserved and ubiquitous death effector domain containing protein, exists predominantly as mono- or diubiquitinated, and that diubiquitinated DEDD interacts with both the K8/18 intermediate filament network and pro-caspase-3. Early in apoptosis, both cytosolic DEDD and its close homologue DEDD2 formed filaments that colocalized with and depended on K8/18 and active caspase-3. Subsequently, these filamentous structures collapsed into intracellular inclusions that migrated into cytoplasmic blebs and contained DEDD, DEDD2, active caspase-3, and caspase-3-cleaved K18 late in apoptosis. Biochemical studies further confirmed that DEDD coimmunoprecipitated with both K18 and pro-caspase-3, and kinetic analyses placed apoptotic DEDD staining prior to caspase-3 activation and K18 cleavage. In addition, both caspase-3 activation and K18 cleavage was inhibited by expression of DEDDDeltaNLS1-3, a cytosolic form of DEDD that cannot be ubiquitinated. Finally, siRNA mediated DEDD knockdown cells exhibited inhibition of staurosporine-induced DNA degradation. Our data suggest that DEDD represents a novel scaffold protein that directs the effector caspase-3 to certain substrates facilitating their ordered degradation during apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins
  • Apoptosis*
  • Carrier Proteins / metabolism
  • Caspase 3
  • Caspases / metabolism
  • DNA / metabolism
  • DNA-Binding Proteins / physiology*
  • Death Domain Receptor Signaling Adaptor Proteins
  • Enzyme Inhibitors / pharmacology
  • Enzyme Precursors / metabolism
  • Female
  • HeLa Cells
  • Humans
  • Inclusion Bodies / chemistry
  • Inclusion Bodies / physiology
  • Inclusion Bodies / ultrastructure
  • Intermediate Filaments / metabolism*
  • Intermediate Filaments / ultrastructure
  • Intracellular Signaling Peptides and Proteins*
  • Jurkat Cells
  • Keratins / metabolism
  • Kinetics
  • Male
  • Membrane Glycoproteins / metabolism
  • Mice
  • Mice, Inbred C3H
  • Mice, Inbred C57BL
  • Nuclear Proteins / metabolism
  • RNA, Small Interfering
  • RNA, Untranslated / metabolism
  • Staurosporine / pharmacology
  • TNF-Related Apoptosis-Inducing Ligand
  • Tumor Cells, Cultured
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Apoptosis Regulatory Proteins
  • Carrier Proteins
  • DEDD protein, human
  • DEDD2 protein, human
  • DNA-Binding Proteins
  • Death Domain Receptor Signaling Adaptor Proteins
  • Dedd protein, mouse
  • Enzyme Inhibitors
  • Enzyme Precursors
  • Intracellular Signaling Peptides and Proteins
  • Membrane Glycoproteins
  • Nuclear Proteins
  • RNA, Small Interfering
  • RNA, Untranslated
  • TNF-Related Apoptosis-Inducing Ligand
  • TNFSF10 protein, human
  • Tnfsf10 protein, mouse
  • Tumor Necrosis Factor-alpha
  • Keratins
  • DNA
  • CASP3 protein, human
  • Casp3 protein, mouse
  • Caspase 3
  • Caspases
  • Staurosporine